BIO301 Current Subjective by Asmat Niazi

BIO301-GENETICS · MIDTERM CURRENT PAPER 10-01-2022 · LION GROUP OF ZOOLOGIST · 1. Quantitative Genetics. (2)

Quantitative genetics is the study of group hereditary for traits determined by many genes simultaneously such as skin color, height, eye color etc .

2. Cluster rule. (2)

Stated that pyrimidines often occur in clusters and hence on the complementary strand purines do likewise.

3. Difference between purines and pyramidines (3) Purines Pyrimidine

Introducti on A purine is a heterocyclic aromatic organic compound, consisting of a pyrimidine ring fused to an Pyrimidine is a heterocyclic aromatic organic compound similar to benzene and pyridine, containing two nitrogen atoms at positions 1 and 3 of the six-member ring. It is isomeric with two other forms of diazine. Function Production of RNA and DNA, proteins and starches, the regulation of enzymes and cell signaling. Production of RNA and DNA, proteins and starches, the regulation of enzymes and cell signaling.

Nucleobas

es

Adenine and guanCytosine, thymine, uracil

Structure

A pyrimidine ring fused to a

Contains two carbon-nitrogen rings and four nitrogen atoms. Contains one carbonnitrogen ring and two nitrogen atoms.

4-Short note on the structure of chromosomes (5) Chromosome Structure: Living organisms are made up of cells. Within cell, there is nucleus or nucleoid region. DNA or chromosomes are present in nucleus/nucleoid region. Chromosome structure: chromosomes are made of DNA and associated proteins. Chromosome carries part or all of a cell’s genetic information. Chromosomes have sister chromatids. Centromere is constricted region, where chromatids are attached. A chromosome constitutes DNA molecule, a protein Histones and supercoiled DNA .

5-Meiosis-1 phases (5) In meiosis I, chromosomes in a diploid cell resegregate, producing four haploid daughter cells. It is this step in meiosis that generates genetic diversity. DNA replication precedes the start of meiosis I. During prophase I, homologous chromosomes pair and form synapses, a step unique to meiosis.

6-Polyploidy

Polyploidy is the heritable condition of possessing more than two complete sets of chromosomes Two major types Autopolyploidy Allopolyploid

7-Non-disjunction When two homologous chromosomes or sister chromatids fail to separate during cell division, such a phenomenon is called as Non-disjunction

Types of Non-disjunction

Meiotic non-disjunction Mitotic non-disjunction

8. Difference Cross over and chiasmata

Chiasmata is the point where two homologous non-sister chromatids exchange genetic material during crossing over whereas crossing over is the process of mutual exchange of segments of non-sister chromatids of homologous chromosomes during the process of meiosis.

9.Environmental factors

Nutrition of mother

The nutrition of the mother can affect the epigenome of a fetus.

Stress hormones

Stress hormones also travel from the mother to a fetus to affect the epigenome

Social interactions and physical activities

Social interactions, physical activity, are factors that affect the epigenome

Exposure to toxins and diet

Exposure to toxins and diet are major factors that affect the epigenome